/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// snd_mem.c: sound caching

#include "quakedef.h"

int			cache_full_cycle;

byte *S_Alloc (int size);

/*
================
ResampleSfx
================
*/
void ResampleSfx (sfx_t *sfx, int inrate, int inwidth, byte *data)
{
    int		    outcount;
    int		    srcsample;
    float	    stepscale;
    int		    i;
    int		    sample, samplefrac, fracstep;
    sfxcache_t	*sc;

    sc = Cache_Check (&sfx->cache);
    if (!sc)
        return;

    stepscale = (float)inrate / shm->speed;	// this is usually 0.5, 1, or 2
    outcount = sc->length / stepscale;
    sc->length = outcount;

    if (sc->loopstart != -1)
    {
        sc->loopstart = sc->loopstart / stepscale;
    }
    sc->speed = shm->speed;

    if (loadas8bit.value)
    {
        sc->width = 1;
    }
    else
    {
        sc->width = inwidth;
    }
    sc->stereo = 0;

// resample / decimate to the current source rate

    if (stepscale == 1 && inwidth == 1 && sc->width == 1)
    {
// fast special case
#ifndef OPENAL
        for (i=0 ; i<outcount ; i++)
        {
            ((signed char *)sc->data)[i] = (int)( (unsigned char)(data[i]) - 128);
        }
#else
        memcpy(sc->data, data, outcount);
#endif
    }
    else
    {
// general case
        samplefrac = 0;
        fracstep = stepscale*256;

        for (i=0 ; i<outcount ; i++)
        {
            srcsample = samplefrac >> 8;
            samplefrac += fracstep;

            if (inwidth == 2)
            {
                sample = LittleShort ( ((short *)data)[srcsample] );
            }
            else
            {
                sample = (int)( (unsigned char)(data[srcsample]) - 128) << 8;
            }

            if (sc->width == 2)
            {
                ((short *)sc->data)[i] = sample;
            }
            else
            {
                ((signed char *)sc->data)[i] = sample >> 8;
            }
        }
    }
}

//=============================================================================

/*
==============
S_LoadSound
==============
*/
sfxcache_t *S_LoadSound (sfx_t *s)
{
    char	    namebuffer[256];
    byte	    *data;
    wavinfo_t	info;
    int		    len;
    float	    stepscale;
    sfxcache_t	*sc;
    byte	    stackbuf[1*1024];		// avoid dirtying the cache heap

// see if still in memory
    sc = Cache_Check (&s->cache);
    if (sc) return sc;

//Con_Printf ("S_LoadSound: %x\n", (int)stackbuf);
// load it in
    Q_strcpy(namebuffer, "sound/");
    Q_strcat(namebuffer, s->name);

//	Con_Printf ("loading %s\n",namebuffer);

    data = COM_LoadStackFile(namebuffer, stackbuf, sizeof(stackbuf));

    if (!data)
    {
        Con_Printf ("Couldn't load %s\n", namebuffer);
        return NULL;
    }

    info = GetWavinfo (s->name, data, com_filesize);
    if (info.channels != 1)
    {
        Con_Printf ("%s is a stereo sample\n",s->name);
        return NULL;
    }

    stepscale = (float)info.rate / shm->speed;
    len = info.samples / stepscale;
    len = len * info.width * info.channels;

    sc = Cache_Alloc ( &s->cache, len + sizeof(sfxcache_t), s->name);

    if (!sc)
    {
        return NULL;
    }
    sc->length = info.samples;
    sc->loopstart = info.loopstart;
    sc->speed = info.rate;
    sc->width = info.width;
    sc->stereo = info.channels;

    ResampleSfx (s, sc->speed, sc->width, data + info.dataofs);

    return sc;
}

/*
===============================================================================

WAV loading

===============================================================================
*/


byte	*data_p;
byte 	*iff_end;
byte 	*last_chunk;
byte 	*iff_data;
int 	iff_chunk_len;


short GetLittleShort(void)
{
    short val = 0;
    val = *data_p;
    val = val + (*(data_p+1)<<8);
    data_p += 2;
    return val;
}

int GetLittleLong(void)
{
    int val = 0;
    val = *data_p;
    val = val + (*(data_p+1)<<8);
    val = val + (*(data_p+2)<<16);
    val = val + (*(data_p+3)<<24);
    data_p += 4;
    return val;
}

void FindNextChunk(char *name)
{
    while (1)
    {
        data_p=last_chunk;

        if (data_p >= iff_end)
        {
            // didn't find the chunk
            data_p = NULL;
            return;
        }
        data_p += 4;

        iff_chunk_len = GetLittleLong();

        if (iff_chunk_len < 0)
        {
            data_p = NULL;
            return;
        }
        data_p -= 8;

        last_chunk = data_p + 8 + ( (iff_chunk_len + 1) & ~1 );

        if (!Q_strncmp((char *) data_p, name, 4)) return;
    }
}

void FindChunk(char *name)
{
    last_chunk = iff_data;
    FindNextChunk (name);
}

/*
============
GetWavinfo
============
*/
wavinfo_t GetWavinfo (char *name, byte *wav, int wavlength)
{
    wavinfo_t	info;
    int     i;
    int     format;
    int		samples;

    memset (&info, 0, sizeof(info));

    if (!wav)
    {
        return info;
    }
    iff_data = wav;
    iff_end = wav + wavlength;

// find "RIFF" chunk
    FindChunk("RIFF");

    if (!(data_p && !Q_strncmp((char *) data_p + 8, "WAVE", 4)))
    {
        Con_Printf("Missing RIFF/WAVE chunks\n");
        return info;
    }

// get "fmt " chunk
    iff_data = data_p + 12;

    FindChunk("fmt ");

    if (!data_p)
    {
        Con_Printf("Missing fmt chunk\n");
        return info;
    }
    data_p += 8;

    format = GetLittleShort();

    if (format != 1)
    {
        Con_Printf("Microsoft PCM format only\n");
        return info;
    }
    info.channels = GetLittleShort();
    info.rate = GetLittleLong();
    data_p += 4+2;
    info.width = GetLittleShort() / 8;

// get cue chunk
    FindChunk("cue ");

    if (data_p)
    {
        data_p += 32;
        info.loopstart = GetLittleLong();
//		Con_Printf("loopstart=%d\n", sfx->loopstart);

        // if the next chunk is a LIST chunk, look for a cue length marker
        FindNextChunk ("LIST");
        if (data_p)
        {
            if (!strncmp ((char *) data_p + 28, "mark", 4))
            {
                // this is not a proper parse, but it works with cooledit...
                data_p += 24;
                i = GetLittleLong ();	// samples in loop
                info.samples = info.loopstart + i;
//				Con_Printf("looped length: %i\n", i);
            }
        }
    }
    else
    {
        info.loopstart = -1;
    }

// find data chunk
    FindChunk("data");

    if (!data_p)
    {
        Con_Printf("Missing data chunk\n");
        return info;
    }
    data_p += 4;
    samples = GetLittleLong () / info.width;

    if (info.samples)
    {
        if (samples < info.samples)
        {
            Sys_Error ("Sound %s has a bad loop length", name);
        }
    }
    else
    {
        info.samples = samples;
    }
    info.dataofs = data_p - wav;

    return info;
}

